Have you considered that it could be harmful to turn on your central heater or air conditioner?

Most of the households thesedays are so concerned about the indoor air quality. You have seen the commercials about those air purifiers that are advertised to make the indoor air clean and fresh. However, would you believe the main entrance of all those contaminants including dust, pollens, bacteria, and dust mite is still wide open? If so, what is the point of turning air purifier on all day and night?

You have to look into what you can not see easily. It is the inside of your air duct system. We tend to ignore what is behind of those air vent registers, no one actually looks inside of their air ducts. But what you don't see can hurt you. Studies have shown that indoor air has 10-15 times more airborne particulate matter than outside air. Furniture, drapes, carpeting, bedding, sheets, and blankets release their own particualte into the air and also collect any that comes into the home environment. Pets also continuously give off animal dander and/or hair.